Knockdown of LncRNA PVT1 inhibits tumorigenesis in non-small-cell lung cancer by regulating miR-497 expression

PVT1 lncRNA in lung cancer: A key player in tumorigenesis and therapeutic opportunities

The lncRNA PVT1 has emerged as a pivotal component in the intricate landscape of cancer pathogenesis, particularly in lung cancer. PVT1, situated in the 8q24 chromosomal region, has garnered attention for its aberrant expression patterns in lung cancer, correlating with tumor progression, metastasis, and poor prognosis. Numerous studies have unveiled the diverse mechanisms PVT1 contributes to lung cancer pathogenesis. It modulates critical pathways, such as cell proliferation, apoptosis evasion, angiogenesis, and epithelial-mesenchymal transition. PVT1's interactions with other molecules, including microRNAs and proteins, amplify its oncogenic influence. Recent advancements in genomic and epigenetic analyses have also illuminated the intricate regulatory networks that govern PVT1 expression. Understanding PVT1's complex involvement in lung cancer holds substantial clinical implications. Targeting PVT1 presents a promising avenue for developing novel diagnostic biomarkers and therapeutic interventions. This abstract encapsulates the expanding knowledge regarding the oncogenic role of PVT1 in lung cancer, underscoring the significance of further research to unravel its complete mechanistic landscape and exploit its potential for improved patient outcomes.

circPVT1 and PVT1/AKT3 show a role in cell proliferation, apoptosis, and tumor subtype-definition in small cell lung cancer

Small cell lung cancer (SCLC) is treated as a homogeneous disease, although the expression of NEUROD1, ASCL1, POU2F3, and YAP1 identifies distinct molecular subtypes. The MYC oncogene, amplified in SCLC, was recently shown to act as a lineage-specific factor to associate subtypes with histological classes. Indeed, MYC-driven SCLCs show a distinct metabolic profile and drug sensitivity. To disentangle their molecular features, we focused on the co-amplified PVT1, frequently overexpressed and originating circular (circRNA) and chimeric RNAs. We analyzed hsa_circ_0001821 (circPVT1) and PVT1/AKT3 (chimPVT1) as examples of such transcripts, respectively, to unveil their tumorigenic contribution to SCLC. In detail, circPVT1 activated a pro-proliferative and anti-apoptotic program when over-expressed in lung cells, and knockdown of chimPVT1 induced a decrease in cell growth and an increase of apoptosis in SCLC in vitro. Moreover, the investigated PVT1 transcripts underlined a functional connection between MYC and YAP1/POU2F3, suggesting that they contribute to the transcriptional landscape associated with MYC amplification. In conclusion, we have uncovered a functional role of circular and chimeric PVT1 transcripts in SCLC; these entities may prove useful as novel biomarkers in MYC-amplified tumors.

The RNA demethylase ALKBH5 promotes the progression and angiogenesis of lung cancer by regulating the stability of the LncRNA PVT1

Background

N6-methyladenosine (m6A) is the most common posttranscriptional modification of RNA and plays critical roles in human cancer progression. However, the biological function of m6A methylation requires further studied in cancer, especially in tumor angiogenesis.

Methods

A public database was used to analyze the expression and overall survival of ALKBH5 and PVT1 in lung cancer patients. CCK-8 and colony formation assays were performed to detect cell proliferation, a transwell assay was used to assess cell migration, and a tube formation assay was performed to assess angiogenic potential in vitro. A zebrafish lung cancer xenograft model was used to verify the function of ALKBH5 and PVT1 in vivo. Western blot assays were used to measure the relative protein expression in lung cancer cells. SRAMP predictor analysis and RNA stability experiments were used to examine the potential m6A modification.

Results

Bioinformatics analysis showed that the expression levels of m6A-related genes were changed significantly in lung cancer tissues compared with normal lung tissues. We then identified that ALKBH5 was upregulated in lung cancer tissues and associated with poor prognosis of lung cancer patients by analyzing a public database. Knockdown of ALKBH5 inhibited the proliferation and migration of cultured lung cancer cell lines. Zebrafish lung cancer xenografts showed that ALKBH5 silencing also suppressed the growth and metastasis of lung cancer cells. Moreover, knockdown of ALKBH5 inhibited the angiogenesis of lung cancer in vitro and in vivo. Mechanistic studies showed that knockdown of ALKBH5 decreased the expression and stability of PVT1 in lung cancer cells. We next observed that PVT1 promoted the progression of lung cancer cells in vitro and in vivo and regulated the expression of VEGFA and angiogenesis in lung cancer. Finally, rescue experiments revealed that ALKBH5 regulated the proliferation, migration and angiogenesis of lung cancer cells, partially through PVT1.

Conclusion

Our results demonstrate that ALKBH5 promotes the progression and angiogenesis of lung cancer by regulating the expression and stability of PVT1, which provides a potential prognostic and therapeutic target for lung cancer patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02770-0.

lncRNA PVT1: a novel oncogene in multiple cancers

Long noncoding RNAs are involved in epigenetic gene modification, including binding to the chromatin rearrangement complex in pre-transcriptional regulation and to gene promoters in gene expression regulation, as well as acting as microRNA sponges to control messenger RNA levels in post-transcriptional regulation. An increasing number of studies have found that long noncoding RNA plasmacytoma variant translocation 1 (PVT1) plays an important role in cancer development. In this review of a large number of studies on PVT1, we found that PVT1 is closely related to tumor onset, proliferation, invasion, epithelial–mesenchymal transformation, and apoptosis, as well as poor prognosis and radiotherapy and chemotherapy resistance in some cancers. This review comprehensively describes PVT1 expression in various cancers and presents novel approaches to the diagnosis and treatment of cancer.

Dysregulated LINC00961 Contributes to the Vitality and Migration of NSCLC Via miR-19a-3p/miR-19b-3p/miR-125b-5p

Accumulating evidence implies that long noncoding RNAs participate in non-small cell lung cancer (NSCLC) tumorigenesis. Our current study synthetically analyzed RNA sequencing data downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. We identified LINC00961 significantly downregulated in NSCLC tissues. We explored the LINC00961 expression in NSCLC tumor tissues and cell lines with reverse transcription-quantitative polymerase chain reaction analysis. Lentivirus-mediated infection upregulated the expression of LINC00961 in A549 cells. The proliferation and migration capability were also measured in A549 cells. In addition, we performed luciferase reporter gene assay to investigate whether LINC00961 directly interacts with miR-19a-3p/miR-19b-3p/miR-125b-5p. A nude mice model was used to detect the potential biological process of LINC00961 on tumor growth in vivo. The results showed that LINC00961 was significantly down-egulated in NSCLC tissues and cell lines. LV-LINC00961 effectively increased the expression of LINC00961 and decreased the expression of miR-19a-3p/miR-19b-3p/miR-125b-5p. LINC00961 upregulation remarkably inhibited cell proliferation, migration, and invasion while promoting cell apoptosis in A549 cells. Luciferase reporter gene assay revealed that LINC00961 could directly sponge miR-19a-3p/miR-19b-3p/miR-125b-5p. Moreover, overexpressed miR-19a-3p/miR-19b-3p/miR-125b-5p reversed the effect of LINC00961 on cell function of A549 cells. Western blot assays revealed that LINC00961 could partially act as a tumor suppressor via affecting PI3K-AKT/MAPK/mTOR signaling pathway. In addition, overexpressed LINC00961-inhibited tumor growth was demonstrated in vivo. Overexpression of LINC00961 inhibited cell viability, invasion, and induced apoptosis in NSCLC, potentially via suppressing the expression of miR-19a-3p/miR-19b-3p/miR-125b-5p by targeting PI3K-AKT/MAPK/mTOR signaling pathways, which might provide the potential biomarker for NSCLC diagnosis and therapies.

Association of lncRNA PVT1 Gene Polymorphisms with the Risk of Essential Hypertension in Chinese Population

Vascular dysfunction and hyperlipidemia are essential risk factors contributing to essential hypertension (EH). The plasmacytoma variant translocation 1 (PVT1) is involved in modulating angiogenesis in tumor tissues and plays an important role in fat differentiation in the progress of obesity. Therefore, we selected two tagSNPs of PVT1 (rs10956390 and rs80177647) to investigate whether they are contributing to the risk of hypertension in Chinese patients. In total, 524 adult patients with EH and 439 matched healthy controls were enrolled for two central of China. Results. PVT1 rs10956390 and rs80177647 polymorphisms were genotyped by using TaqMan assay. PVT1 rs10956390 TT genotype was associated with a decreased risk of EH (OR = 0.561, 95% CI = 0.372-0.846, P = 0.006), while rs80177647 TA genotype was associated with an increased risk (OR = 2.236, 95% CI = 1.515-3.301, P < 0.001). Rs10956390 T allele was associated with lower triglyceride levels in the plasma both from healthy and EH donors. What is more, there is an association between rs10956390 polymorphism and HDL-C level, as well as LDL-C. Conclusion. PVT1 rs10956390 and rs80177647 polymorphisms may contribute to the risk of EH in Chinese population by regulating blood lipid levels.

PVT1 is a prognostic marker associated with immune invasion of bladder urothelial carcinoma

Plasmacytoma variant translocation 1 (PVT1) is involved in multiple signaling pathways and plays an important regulatory role in a variety of malignant tumors. However, its role in the prognosis and immune invasion of bladder urothelial carcinoma (BLCA) remains unclear. This study investigated the expression of PVT1 in tumor tissue and its relationship with immune invasion, and determined its prognostic role in patients with BLCA. Patients were identified from the cancer genome atlas (TCGA). The enrichment pathway and function of PVT1 were explained by gene ontology (GO) term analysis, gene set enrichment analysis (GSEA) and single-sample gene set enrichment analysis (ssGSEA), and the degree of immune cell infiltration was quantified. Kaplan-Meier analysis and Cox regression were used to analyze the correlation between PVT1 and survival rate. PVT1-high BLCA patients had a lower 10-year disease-specific survival (DSS P < 0.05) and overall survival (OS P < 0.05). Multivariate Cox regression analysis showed that PVT1 (high vs. low) (P = 0.004) was an independent prognostic factor. A nomogram was used to predict the effect of PVT1 on the prognosis. PVT1 plays an important role in the progression and prognosis of BLCA and can be used as a medium biomarker to predict survival after cystectomy.

miR-497 defect contributes to gastric cancer tumorigenesis and progression via regulating CDC42/ITGB1/FAK/PXN/AKT signaling

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. MicroRNAs (miRNAs) are known to be important regulators of GC. This study aims to investigate the role of miRNA (miR)-497 in GC. We demonstrated that the expression of miR-497 was downregulated in human GC tissues. After N-methyl-N-nitrosourea treatment, the incidence of GC in miR-497 knockout mice was significantly higher than that in wild-type mice. miR-497 overexpression suppressed GC cell proliferation, cell-cycle progression, colony formation, anti-apoptosis ability, and cell migration and invasion capacity. Additionally, miR-497 overexpression decreased the expression levels of cell division cycle 42 (CDC42) and integrin β1 (ITGB1) and inhibited the phosphorylation of focal adhesion kinase (FAK), paxillin (PXN), and serine-threonine protein kinase (AKT). Furthermore, overexpression of miR-497 inhibited the metastasis of GC cells in vivo, which could be counteracted by CDC42 restoration. Furthermore, the focal adhesion of GC cells was found to be regulated by miR-497/CDC42 axis via ITGB1/FAK/PXN/AKT signaling. Collectively, it is concluded that miR-497 plays an important role in the repression of GC tumorigenesis and progression, partly via the CDC42/ITGB1/FAK/PXN/AKT pathway.

LncRNA-PVT1 activates lung fibroblasts via miR-497-5p and is facilitated by FOXM1

It is little known about the lncRNA-PVT1 effect on occupational pulmonary fibrosis, although researches show it plays an essential role in cancer. Studies reveal that lung fibroblast activation is one of the key events in silica-induced fibrosis. Here, we found that lncRNA-PVT1 promoted the proliferation, activation, and migration of lung fibroblasts. The isolation of cytoplasmic and nuclear RNA assay and fluorescence in situ hybridization experiment showed that lncRNA-PVT1 was abundantly expressed in the cytoplasm. Luciferase reporter gene assay and RNA pull-down experiment indicated that the cytoplasmic-localized lncRNA-PVT1 could competitively bind miR-497-5p. MiR-497-5p was further observed to attenuate silica-induced pulmonary fibrosis by targeting Smad3 and Bcl2. Moreover, the transcription factor FOXM1 acted as a profibrotic factor by elevating lncRNA-PVT1 transcription in lung fibroblasts. Inhibition of FOXM1 expression with thiostrepton alleviated silica-induced pulmonary fibrosis in vivo. Collectively, we revealed that FOXM1-facilitated lncRNA-PVT1 activates lung fibroblasts via miR-497-5p during silica-induced pulmonary fibrosis, which may provide potential therapeutic targets for pulmonary fibrosis.

lncRNA PVT1 Promotes Metastasis of Non-Small Cell Lung Cancer Through EZH2-Mediated Activation of Hippo/NOTCH1 Signaling Pathways

Objective:

Although growing evidences have showed that long non-coding RNA (lncRNAs) plasmacytoma variant translocation 1 (PVT1) plays a critical role in the progression of non-small cell lung cancer (NSCLC), there are still many unsolved mysteries remains to be deeply elucidated. This study aimed to find a new underlying mechanism of PVT1 in regulating the tumorigenesis and development of NSCLC.

Materials and Methods:

In this experimental study, Quantitative reverse transcription polymerase chain reaction (qRTPCR) was used to profile the expression of PVT1 in NSCLC tissues and cells. The effects of PVT1 on cell growth, migration and invasion were detected by colony formation assay, Matrigel-free transwell and Matrigel transwell assays, respectively. Changes of the key protein expression in Hippo and NOTCH signaling pathways, as well as epithelialmesenchymal transition (EMT) markers, were analyzed using western blot. Interaction of PVT1 with enhancer of zeste homolog 2 (EZH2) was verified by RNA pull-down, and their binding to the downstream targets was detected by Chromatin Immunoprecipitation (ChIP) assays.

Results:

These results showed that PVT1 was up-regulated in NSCLC tissue and cell lines, promoting NSCLC cell proliferation, migration and invasion. Knockdown of PVT1 inhibited the expression of Yes-associated protein 1 (YAP1) and NOTCH1 signaling activation. Further, we have confirmed that PVT1 regulated expression of YAP1 through EZH2-mediated miR-497 promoter methylation resulting in the inhibition of miR-497 transcription and its target YAP1 upregulation, and finally NOTCH signaling pathway was activated, which promoted EMT and invasion and metastasis.

Conclusion:

These results suggested that lncRNA PVT1 promotes NSCLC metastasis through EZH2-mediated activation of Hippo/NOTCH1 signaling pathways. This study provides a new opportunity to advance our understanding in the potential mechanism of NSCLC development.

The effects of LncRNA PVT1 on clinical characteristics and survival in breast cancer patients: A protocol for systematic review and meta analysis

BACKGROUND

Currently, an increasing number of long noncoding RNAs (LncRNAs) have been reported to be abnormally expressed in human carcinomas and play a vital role in tumourigenesis. Some studies were carried out to investigate the influence of the expression of plasmacytoma variant translocation 1 (PVT1) on prognosis and its clinical significance in patients with breast cancer, while the results were contradictory and uncertain. A meta-analysis was conducted with controversial data to accurately assess the issue.

METHODS

A detailed search of relevant researches was performed in Wanfang, Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, Chongqing VIP Chinese Science and Technology Periodical Database, PubMed, Embase, and Web of Science. Two reviewers independently conducted data extraction and literature quality evaluation. Odd ratio and its 95% confidence intervals were applied to evaluate the relationship between PVT1 and clinicopathological characteristics of breast cancer patients. Hazard ratios and its 95% confidence intervals were adopted to assess the prognostic effects of PVT1 on overall survival and disease-free survival. Meta-analysis was conducted with Stata 14.0 software.

RESULTS

This study will provide high-quality evidence-based medical evidence for the correlation between PVT1 expression and overall survival, and disease-free survival and clinicopathological features.

CONCLUSION

The study will provide updated evidence to evaluate whether the expression of PVT1 is in association with poor prognosis in patients with breast cancer.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/C2TYE.

PVT1: A long non-coding RNA recurrently involved in neoplasia-associated fusion transcripts

NGS technologies and bioinformatics tools allow the rapid identification of chimeric transcripts in cancer. More than 40,000 fusions are so far reported in the literature; however, for most of them, the role in oncogenesis is still not fully understood. This is the case for fusions involving the long non-coding RNA (lncRNA) Plasmacytoma variant translocation 1 (PVT1) (8q24.21). This lncRNA displays oncogenic functions in several cancer types interacting with microRNAs and proteins, but the role of PVT1 fusion transcripts is more obscure. These chimeras have been identified in both hematological malignancies and solid tumors, mainly arising from rearrangements and/or amplification of the 8q24 chromosomal region. In this review, we detail the full spectrum of PVT1 fusions in cancer, summarizing current knowledge about their genesis, function, and role as biomarkers.

Long non-coding RNA CCAT1 promotes non-small cell lung cancer progression by regulating the miR-216a-5p/RAP2B axis

The long non-coding RNA colon cancer-associated transcript 1 (CCAT1) has been investigated to involve in the progression of non-small cell lung cancer (NSCLC). Thus, this study aims to explore the detailed molecular mechanisms of CCAT1 in NSCLC. The expression of CCAT1, miR-216a-5p, RAP2B, Bax, Bcl-2, and cleaved caspase 3 was detected by qRT-PCR or Western blot. Cell proliferation, apoptosis, migration, and invasion were analyzed using cell counting kit-8, flow cytometry or Transwell assays, respectively. The interaction between miR-216a-5p and CCAT1 or RAP2B was analyzed by luciferase reporter, RNA immunoprecipitation, and pull-down assays. The expression of CCAT1 was elevated in NSCLC, and CCAT1 deletion could inhibit NSCLC cell proliferation, migration, and invasion but induce apoptosis in vitro as well as imped tumor growth in vivo. MiR-216a-5p was confirmed to be a target of CCAT1, and silencing miR-216a-5p could reverse CCAT1 depletion-mediated inhibitory effects on cell tumorigenesis in NSCLC. Besides that, miR-216a-5p was decreased in NSCLC, and miR-216a-5p restoration inhibited cell tumorigenesis by regulating RAP2B, which was verified to be a target of miR-216a-5p. Additionally, co-expression analysis suggested that CCAT1 indirectly regulated RAP2B level by targeting miR-216a-5p in NSCLC cells. Taken together, CCAT1 deletion could inhibit cell progression in NSCLC through miR-216a-5p/RAP2B axis, indicating a novel pathway underlying NSCLC cell progression and providing new potential targets for NSCLC treatment.

Long non-coding RNA CASC19 facilitates non-small cell lung cancer cell proliferation and metastasis by targeting the miR-301b-3p/LDLR axis

BACKGROUND

Non-small cell lung cancer (NSCLC) is a lethal tumor resulting in a large number of cancer-related deaths globally. Long noncoding RNAs (lncRNAs) may modulate tumor initiation and metastasis. Although dysregulation of lncRNA cancer susceptibility 19 (CASC19) is validated in NSCLC, further exploration of the CASC19-regulated mechanism in NSCLC is still needed.

METHODS

CASC19 expression was examined in NSCLC cells by a quantitative reverse transcriptase-polymerase chain reaction. The specific role of CASC19 in NSCLC was analyzed by cell counting kit-8, EdU, Transwell and western blot assays. The interaction between miR-301b-3p and CASC19 or low-density lipoprotein receptor (LDLR) was confirmed by luciferase reporter and RNA immunoprecipitation assays.

RESULTS

CASC19 is markedly overexpressed in NSCLC. Its deficiency impairs cell proliferation, as well as metastasis in NSCLC. Molecular mechanism experiments indicated that CASC19 negatively modulates the expression of miR-301b-3p and miR-301b-3p can bind with CASC19 in NSCLC. In addition, miR-301b-3p binds to LDLR to impair its expression in NSCLC. Finally, rescue experiments showed that miR-301b-3p inhibition or LDLR overexpression counteracted the CASC19 knockdown-mediated function on cell proliferation and metastasis in NSCLC.

CONCLUSIONS

CASC19 facilitates NSCLC cell proliferation and metastasis by targeting the miR-301b-3p/LDLR axis, offering a possible strategy for lncRNA-targeted treatment in NSCLC.

Regulation of microRNA-497 expression in human cancer

MicroRNAs (miRNAs/miRs) are a type of non-coding single-stranded RNA, with a length of ~22 nt, which are encoded by endogenous genes and are involved in the post-transcriptional regulation of gene expression in animals and plants. Studies have demonstrated that miRNAs play an important role in the occurrence, development, metastasis, diagnosis and treatment of cancer. In recent years, miR-497 has been identified as one of the key miRNAs in a variety of cancer types and has been shown to be downregulated in a variety of solid tumors. However, the regulation of miR-497 expression involves a complex network, which is affected by several factors. The aim of the present review was to summarize the mechanism of regulation of miR-497 expression at the pre-transcriptional and transcriptional levels in cancer, as well as the role of miR-497 expression imbalance in cancer diagnosis, treatment and prognosis. The regulatory mechanisms of miR-497 expression may aid in our understanding of the causes of miR-497 expression imbalance and provide a reference value for further research on the diagnosis and treatment of cancer.

The lncRNA PVT1 promotes invasive growth of lung adenocarcinoma cells by targeting miR-378c to regulate SLC2A1 expression

As an oncogene, plasmacytoma variant translocation 1 (PVT1) has been found to be highly expressed in several cancers. However, its specific role in lung adenocarcinoma (ADC) has not been fully elucidated. In this study, the expression of PVT1, miR-378c, and solute carrier family 2 member 1 (SLC2A1) was determined by quantitative real-time PCR and western blot. Dual-luciferase reporter assay was used to explore the relationship between PVT1 and miR-378c, as well as miR-378c and SLC2A1. The effects of PVT1 on the lung ADC cells proliferation, invasion, and migration were detected using MTT, wound-healing, and transwell assays. The results revealed that PVT1 was highly expressed in lung ADC cells, and the overexpression of PVT1 promoted the proliferation, migration, and invasion of lung ADC cells. In lung ADC cells, PVT1 negatively regulated miR-378c expression, and miR-378c negatively regulated SLC2A1 expression through binding to its 3'-untranslated coding regions. Knocking down of PVT1 inhibited the abilities of cell proliferation, migration, and invasion, while miR-378c inhibitor or SLC2A1 Vector diminished the effect. Together, silencing PVT1 downregulated SLC2A1 expression via targeting miR-378c, and then repressed lung ADC cells growth, migration, and invasion.

miR-497 induces apoptosis by the IRAK2/NF-κB axis in the canine mammary tumour

Since companion dogs have the same living environment as humans, they are a good animal model for the study of human diseases; this is especially true of canine spontaneous mammary tumours models. A better understanding of the natural history and molecular mechanisms of canine mammary tumour is of great significance in comparative medicine. Here, we collected canine mammary tumour cases and then assayed the clinical cases by pathological examination and classification by HE staining and IHC. miRNA-497 family members (miR-497, miR-16, miR-195 and miR-15) were positively correlated with the breast cancer marker genes p63 and PTEN. Modulation of the expression of miR-497 in the canine mammary tumour cell lines CMT1211 and CMT 7364 induced apoptosis and inhibited cell proliferation. Mechanistically, IRAK2 was shown to be a functional target of miR-497 that affects the characteristics of cancer cells by inhibiting the activity of the NF-κB pathway. Overall, our work reveals the miR-497/IRAK2/NF-κB axis as a vital mechanism of canine mammary tumour progression and suggests this axis as a target in breast cancer.

LncRNA SNHG7 promotes the proliferation of nasopharyngeal carcinoma by miR-514a-5p/ELAVL1 axis

Background

Nasopharyngeal carcinoma (NPC), with distinct geographical distribution, has gathered public attention. Despite that radiotherapy and chemotherapy are applied to treat NPC, cell metastasis still cannot be avoided. Numerous works have elucidated that lncRNAs are essential players in the development of multiple cancers. LncRNA SNHG7 has been reported as a contributing factor in the occurrence of certain cancers, but its mechanism in NPC deserves further investigation. The purpose of the study is to figure out the role and molecular regulation mechanism of SNHG7 in NPC.

Methods

The role of SNHG7 in NPC was verified by CCK-8, colony formation, EdU staining, western blot and capase-3 assays. The interactions between SNHG7/ELAVL1 and miR-514a-5p were confirmed by RNA pull down, RT-qPCR, RIP and luciferase reporter assays.

Results

SNHG7 was upregulated in NPC cells, and absence of SNHG7 suppressed cell proliferation as well as promoted cell apoptosis in NPC. Furthermore, SNHG7 was confirmed to bind with miR-514a-5p and negatively modulate miR-514a-5p expression. Besides, miR-514a-5p was found to be able to bind with ELAVL1 and negatively regulate ELAVL1 mRNA and protein expressions. In the end, rescue assays demonstrated that the miR-514a-5p deficiency restored the NPC progression inhibited by SNHG7 silence, and ELAVL1 partly counteracted the restoration caused by miR-514a-5p inhibitor in HNE1 cells.

Conclusions

LncRNA SNHG7 promotes the proliferation and migration of nasopharyngeal carcinoma by miR-514a-5p/ ELAVL1 axis.

LIMD1-AS1 suppressed non-small cell lung cancer progression through stabilizing LIMD1 mRNA via hnRNP U

Background

Non‐small cell lung cancer (NSCLC) occupies the majority of lung cancer cases and is notorious for the awful prognosis. LIM domains‐containing 1 (LIMD1) is suggested as a tumor suppressor in lung cancer, but its mechanism in NSCLC remains elusive. Present study aimed to uncover the mechanism of LIMD1 in NSCLC.

Methods

qRT‐PCR was performed to analyze the level of LIMD1. The functions of LIMD1 in NSCLC cells were evaluated by CCK‐8, EdU, and caspase‐3 activity assays. RIP and pull‐down assays were applied to determine the interaction of LIMD1 with heterogeneous nuclear ribonucleoprotein U (hnRNP U) and LIMD1‐AS1.

Results

LIMD1 was downregulated in NSCLC samples and cells. Functionally, LIMD1 hindered proliferation and drove apoptosis in NSCLC cells. Moreover, long noncoding RNA (lncRNA) LIMD1 antisense RNA 1 (LIMD1‐AS1) was downregulated in NSCLC samples and cell lines. LIMD1‐AS1 knockdown abrogated NSCLC cell growth in vitro and in vivo. Mechanistically, LIMD1‐AS1 stabilized LIMD1 mRNA through interacting with hnRNP U. Rescue experiments suggested that LIMD1‐AS1 repressed NSCLC progression through LIMD1.

Conclusions

LIMD1‐AS1 suppressed NSCLC progression through stabilizing LIMD1 mRNA via hnRNP U, providing new thoughts for the improvement of molecular‐targeted therapy for NSCLC.

lncRNA SNHG11 promotes lung cancer cell proliferation and migration via activation of Wnt/β-catenin signaling pathway

Lung cancer ranks topmost among the most frequently diagnosed cancers. Despite increasing research, there are still unresolved mysteries in the molecular mechanism of lung cancer. Long noncoding RNA small nucleolar RNA host gene 11 (SNHG11) was found to be upregulated in lung cancer and facilitated lung cancer cell proliferation, migration, invasion, and epithelial-mesenchymal transition progression while suppressed cell apoptosis. Moreover, the high expression of SNHG11 was correlated with poor prognosis of lung cancer patients, TNM stage, and tumor size. Further assays demonstrated that SNHG11 functioned in lung cancer cells via Wnt/β-catenin signaling pathway. Subsequently, Wnt/β-catenin pathway was found to be activated through SNHG11/miR-4436a/CTNNB1 ceRNA axis. As inhibiting miR-4436 could only partly rescue the suppression of cell function induced by silencing SNHG11, it was suspected that β-catenin might enter cell nucleus through other pathways. Mechanism investigation proved that SNHG11 would directly bind with β-catenin to activate classic Wnt pathway. Subsequently, in vivo tumorigenesis was also demonstrated to be enhanced by SNHG11. Hence, SNHG11 was found to promote lung cancer progression by activating Wnt/β-catenin pathway in two different patterns, implying that SNHG11 might contribute to lung cancer treatment by acting as a therapeutic target.

Long non-coding RNA PVT1 contributes to cell growth and metastasis in non-small-cell lung cancer by regulating miR-361-3p/SOX9 axis and activating Wnt/β-catenin signaling pathway

Lung cancer is the most frequent cause of cancer-related mortality in men, and 85 % of lung cancer is diagnosed as non-small-cell lung cancer (NSCLC). Plasmacytoma variant translocation1 (PVT1) serves as an oncogenic factor in NSCLC. However, the pathogenesis of PVT1 in NSCLC is still vague. The expression levels of PVT1, sex determining region Y (SRY)-related high mobility group (HMG)-box9 (SOX9), and microRNA (miR)-361-3p in NSCLC tissues and cells were detected by quantitative real-time polymerase chain reaction (RT-qPCR). The protein levels of SOX9, β-catenin, and c-Myc were detected by western blot assay. Cell proliferation, apoptosis, migration and invasion were measured by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), flow cytometry, transwell assays, severally. The interaction between miR-361-3p and PVT1 or SOX9was predicted by starBase, and then verified by the dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays. PVT1 and SOX9 was highly expressed in NSCLC tumor tissues and cells. PVT1 facilitated proliferation, migration, invasion and hindered apoptosis of NSCLC cells. MiR-361-3p was a target of PVT1 in NSCLC cells. SOX9 acted as a target of miR-361-3p. PVT1 worked as a miR-361-3p sponge to regulate SOX9 expression. PVT1 modulate the Wnt/β-catenin Signaling Pathway by miR-361-3p/SOX9 axis. Our studies disclosed that PVT1 boosted proliferation, migration, invasion and curbed apoptosis by miR-361-3p/SOX9 axis, providing the possible therapeutic strategy for NSCLC.

Non-coding RNA profile in lung cancer

Lung cancer is the most frequently diagnosed malignancy and the leading source of cancer-associated mortality. This kind of cancer has heterogeneous nature and is divided into two broad classes of small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). In addition to aberrant expression of several signaling pathways and oncogenes, lung cancer is associated with dysregulation of expression of non-coding RNAs including both long non-coding RNAs (lncRNAs) and miRNAs. These aberrantly expressed transcripts are putative therapeutic targets and diagnostic/ prognostic markers. Integrative assessment of expression of lncRNAs, miRNAs and mRNAs has led to construction of competing endogenous RNA networks in which several lncRNAs act as molecular sponges to inhibit regulatory function of miRNAs on mRNAs. Notably, some of these networks seem to have subtype-specific functions in lung cancer. In this review, we summarize recent findings about the importance of these networks in the pathogenesis of lung cancer and provide a list of onco-miRNAs, tumor suppressor miRNAs, oncogenic lncRNAs and tumor suppressor lncRNAs based on their roles in the carcinogenic process in lung cancer.

The USP21/YY1/SNHG16 axis contributes to tumor proliferation, migration, and invasion of non-small-cell lung cancer

Deubiquitinases (DUBs) and noncoding RNAs have been the subjects of recent extensive studies regarding their roles in lung cancer, but the mechanisms involved are largely unknown. In our study, we used The Cancer Genome Atlas data set and bioinformatics analyses and identified USP21, a DUB, as a potential contributor to oncogenesis in non-small-cell lung cancer (NSCLC). We further demonstrated that USP21 was highly expressed in NSCLCs. We then conducted a series of in vitro and in vivo assays to explore the effect of USP21 on NSCLC progression and the underlying mechanism involved. USP21 promoted NSCLC cell proliferation, migration, and invasion and in vivo tumor growth by stabilizing a well-known oncogene, Yin Yang-1 (YY1), via mediating its deubiquitination. Furthermore, YY1 transcriptionally regulates the expression of SNHG16. Moreover, StarBase bioinformatics analyses predicted that miR-4500 targets SNHG16 and USP21. A series of in vitro experiments indicated that SNHG16 increased the expression of USP21 through miR-4500. In summary, the USP21/YY1/SNHG16 axis plays a role in promoting the progression of NSCLC. Therefore, the USP21/YY1/SNHG16/miR-4500 axis may be a potential therapeutic target in NSCLC treatment.

Therapies targeting a molecular feedback loop involved in tumor growth may prove valuable for treating non-small-cell lung cancer. Fangbao Ding, Jianbing Huang, and co-workers at Shanghai Jiao Tong University in Shanghai, China, have shown how an enzyme called USP21 promotes cancer cell proliferation and tumor growth in non-small-cell lung cancer. The team took cancerous and non-cancerous lung tissue samples from 42 patients, and analyzed the expression and behavior of USP21. The enzyme was highly expressed in cancerous tissues, where it stabilized a known gene with the potential to cause cancer called YY1. This gene also regulated the expression of a particular RNA molecule, which in turn worked to increase levels of USP21. This cyclical process encouraged the proliferation, migration and invasion of non-small-cell lung cancer cells, and may provide a future therapeutic target.

Long Non-Coding RNA PVT1 Regulates BAMBI To Promote Tumor Progression In Non-Small Cell Lung Cancer By Sponging miR-17-5p

Background

Non-small cell lung cancer (NSCLC) is a common malignancy over the world. Previous report indicated that the plasmacytoma variant translocation 1 (PVT1) has been documented to function as an oncogene in various types of human cancers. However, the biological mechanism of PVT1 was still rarely reported in NSCLC.

Methods

The levels of PVT1, miR-17-5p, and bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) in NSCLC tissues (n=64) and cells (H1299 and A549) were detected by qRT-PCR and immunohistochemistry (IHC). The protein level of BAMBI was measured by Western blot assay. Cell viability and apoptotic rate were evaluated by MTT assay and flow cytometry, respectively. The migrated and invaded abilities were assessed by Transwell assay and Wound healing assay. The interactions between miR-17-5p and PVT1 or BAMBI were predicted by starBase v2.0 and TargetScan, respectively, and then dual-luciferase reporter assay and RNA pull-down assay were performed to verify these interactions. The mice model experiments were constructed to further validate the roles of PVT1 in vivo.

Results

The levels of PVT1 and BAMBI were both apparently increased, and miR-17-5p was declined in NSCLC tissues and cells. The depletion of PVT1 or BAMBI blocked cell viability, migrated and invaded abilities but impelled apoptotic rate in A549 and H1299 cells. PVT1 was validated as a sponge to miR-17-5p and BAMBI was a direct target of miR-17-5p. PVT1 promoted cell viability, migrated and invaded abilities but repressed apoptotic rate by targeting BAMBI. MiR-17-5p regulated cell behaviors mediated by PVT1. PVT1 silencing decreased BAMBI expression by sponging miR-17-5p. In addition, PVT1 knockdown blocked the xenograft tumor growth in vivo.

Conclusion

These results manifested that PVT1 modulated BAMBI to promote tumor progression in NSCLC by sponging miR-17-5p. Thus, the novel regulatory pathway may provide a new therapeutic target for NSCLC patients.

Long Non-coding RNA PVT1 as a Prognostic and Therapeutic Target in Pediatric Cancer

In recent decades, biomedical research has focused on understanding the functionality of the human translated genome, which represents a minor part of all genetic information transcribed from the human genome. However, researchers have become aware of the importance of non-coding RNA species that constitute the vast majority of the transcriptome. In addition to their crucial role in tissue development and homeostasis, mounting evidence shows non-coding RNA to be deregulated and functionally contributing to the development and progression of different types of human disease including cancer both in adults and children. Small non-coding RNAs (i.e., microRNA) are in the vanguard of clinical research which revealed that RNA could be used as disease biomarkers or new therapeutic targets. Furthermore, many more expectations have been raised for long non-coding RNAs, by far the largest fraction of non-coding transcripts, and still fewer findings have been translated into clinical applications. In this review, we center on PVT1, a large and complex long non-coding RNA that usually confers oncogenic properties on different tumor types. We focus on the compilation of early advances in the field of pediatric tumors which often lags behind clinical improvements in adult tumors, and provide a rationale to continue studying PVT1 as a possible functional contributor to pediatric malignancies and as a potential prognostic marker or therapeutic target.

The characteristics of lung cancer in Xuanwei County: A review of differentially expressed genes and noncoding RNAs on cell proliferation and migration

The occurrence of lung cancers is the highest in Xuanwei County, Yunnan province, China, especially among nonsmoking women. Domestic combustion of smoky coal induces serious indoor air pollution and is considered to be the main cause of human lung cancers. The occurrence of lung cancer in Xuanwei County has unique characteristics, such as the high morbidity in nonsmoking women or people with no family history. In the present review, we summarize advances in identification of differentially expressed genes, regulatory lncRNAs and miRNAs in cell proliferation and migration of lung cancers in Xuanwei County. Moreover, several regulatory differentially expressed genes (DEGs) or noncoding RNAs have diagnostic and prognostic significance for lung cancers in Xuanwei County and have the potential to serve as biomarkers.

Comprehensive investigation of the clinical significance and molecular mechanisms of plasmacytoma variant translocation 1 in sarcoma using genome-wide RNA sequencing data

Objective: The present study aims to identify the potential clinical application and molecular mechanism of plasmacytoma variant translocation 1 (PVT1) in patients with sarcomas by mining an RNA sequencing dataset from The Cancer Genome Atlas (TCGA) through multiple genome-wide analysis approaches.

Methods: A genome-wide RNA sequencing dataset was downloaded from TCGA, survival analysis was used to evaluate the prognostic value of PVT1 in sarcoma. The potential mechanism was investigated by multiple tools: Database for Annotation, Visualization, and Integrated Discovery v6.8, gene set enrichment analysis (GSEA), and Connectivity Map (CMap).

Results: Comprehensive survival analysis indicated that overexpression of PVT1 was significantly associated with poor prognosis in patients with sarcoma, and nomogram demonstrated that PVT1 contributed more than other traditional clinical parameters in sarcoma survival prediction. Weighted gene co-expression network analysis identified ten hub differentially expressed genes (DEGs) between sarcoma tissues with low and overexpression of PVT1, and substantiated that these DEGs have a complex co-expression network relationship. CMap analysis has identified that antipyrine, ondansetron, and econazole may be candidate targeted drugs for sarcoma patients with PVT1 overexpression. GSEA revealed that overexpression of PVT1 may be involved in the posttranscriptional regulation of gene expression, tumor invasiveness and metastasis, osteoblast differentiation and development, apoptosis, nuclear factor kappa B, Wnt, and apoptotic related signaling pathways.

Conclusions: Our findings indicate that PVT1 may serve as a prognostic indicator in patients with sarcoma. Its underlying mechanism is revealed by GSEA, and CMap offers three candidate drugs for the individualized targeted therapy of sarcoma patients with overexpression of PVT1.

Chemoresistance Mediated by ceRNA Networks Associated With the PVT1 Locus

Competitive endogenous RNA (ceRNA) networks have emerged as critical regulators of carcinogenesis. Their activity is mediated by various non-coding RNAs (ncRNAs), including long non-coding RNAs and microRNAs, which competitively bind to targets, thereby modulating gene expression and activity of proteins. Of particular interest, ncRNAs encoded by the 8q24 chromosomal region are associated with the development and progression of several human cancers, most prominently lncPVT1. Chemoresistance presents a significant obstacle in the treatment of cancer and is associated with dysregulation of normal cell processes, including abnormal proliferation, differentiation, and epithelial-mesenchymal transition. CeRNA networks have been shown to regulate these processes via both direct sponging/repression and epigenetic mechanisms. Here we present a review of recent literature examining the contribution of ncRNAs encoded by the PVT1 locus and their associated ceRNA networks to the development of resistance to common chemotherapeutic agents used to treat human cancers.

Regulatory Mechanisms and Clinical Applications of the Long Non-coding RNA PVT1 in Cancer Treatment

Cancer is the second leading cause of death worldwide, and no obvious decline in incidence and mortality has occurred in recent years. It is imperative to further investigate the mechanisms underlying tumor progression. Long non-coding RNAs have received considerable attention in recent years because of their major regulatory roles in gene expression. Among them, PVT1 is well-studied, and substantial evidence indicates that PVT1 plays critical roles in the onset and development of cancers. Normally, PVT1 acts as an oncogenic factor by promoting cancer cell proliferation, invasion, metastasis, and drug resistance. Herein, we summarize current knowledge regarding the regulatory effects of PVT1 in cancer progression, as well as the related underlying mechanisms, such as interaction with Myc, modulation of miRNAs, and regulation of gene transcription and protein expression. In extracellular fluid, PVT1 mainly promotes cancer initiation, and it normally enhances cellular cancer characteristics in the cytoplasm and cell nucleus. Regarding clinical applications, its role in drug resistance and its potential use as a diagnostic and prognostic marker have received increasing attention. We hope that this review will contribute to a better understanding of the regulatory role of PVT1 in cancer progression, paving the way for the development of PVT1-based therapeutic approaches in cancer treatment.

Long non‑coding RNAs in lung cancer: Regulation patterns, biologic function and diagnosis implications (Review)

Lung cancer is the most common malignancy with the highest mortality worldwide. Emerging research has demonstrated that long non-coding RNAs (lncRNAs), a key genomic product, are commonly dysregulated in lung cancer and have significant functions in lung cancer initiation, progression and therapeutic response. lncRNAs may interact with DNA, RNA or proteins, as tumor suppressor genes or oncogenes, to regulate gene expression and cell signaling pathways. In the present review, first a summary was presented of the causal effects of dysregulated lncRNAs in lung cancer. Next, the function and specific mechanisms of lncRNA-mediated tumorigenesis, metastasis and drug resistance in lung cancer were discussed. Finally, the potential roles of lncRNAs as biomarkers for lung cancer were explored.

Long noncoding RNA PVT1: A highly dysregulated gene in malignancy

Recent studies have verified the contribution of several long noncoding RNAs (lncRNAs) in the carcinogenesis. Among the highly acknowledged lncRNAs is the human homolog of the plasmacytoma variant translocation gene, which is called PVT1. PVT1 resides near Myc oncogene and regulates the oncogenic process through modulation of several signaling pathways, such as TGF-β, Wnt/ β-catenin, PI3K/AKT, and mTOR pathways. This lncRNA has a circular form as well. Expression analyses and functional studies have appraised the oncogenic roles of PVT1 and circPVT1. Experiments in several cancer cell lines have shown that PVT1 silencing suppresses cancer cell proliferation, whereas its overexpression has the opposite effect. Its silencing has led to the accumulation of cells in the G0/G1 phase and diminished the number of cells in the S phase. Moreover, genome-wide association studies have signified the role of single nucleotide polymorphisms of this lncRNA in conferring risk of lymphoma in different populations. In the current study, we have summarized recent data about the role of PVT1 and circPVT1 in the carcinogenesis process.

Long non‑coding RNA plasmacytoma variant translocation 1 gene promotes the development of cervical cancer via the NF‑κB pathway

The long noncoding RNA plasmacytoma variant translocation 1 gene (LncRNA PVT1) has an important role in tumor occurrence and development, yet the role and underlying molecular mechanisms of this RNA in cervical cancer have not yet been elucidated. In the present study, three cervical cancer cell lines (HeLa, Ca Ski and SiHa) were used to verify how LncRNA PVT1 mediates cervical cancer development, and the H8 cell line was used as a control. A LncRNA PVT1 overexpression vector or small interfering RNAs targeting LncRNA PVT1 were transfected into cervical cancer cells to generate LncRNA PVT1 overexpression and silencing in these cells. LncRNA PVT1 overexpression accelerated the growth of cervical cancer cells by advancing the cell cycle and inhibiting cellular apoptosis; increases in Cyclin D1 (CCND1) mRNA and activated Bcl‑2 protein expression levels also supported this finding. Furthermore, NF‑κB activation and expression was increased by LncRNA PVT1 overexpression. In addition, NF‑κB activation or inhibition induced changes in cell viability, accompanied by changes in CCND1 and Bcl‑2 expression. Increases or decreases in microRNA‑16 (miR‑16) expression (using miR mimics and inhibitors) also corresponded to changes in LncRNA PVT1 expression, in vitro. miR‑16 mimics and inhibitor had opposite effects to those of NF‑κB activity, and miR‑16 was demonstrated to directly interact with the NF‑κB gene as measured using the dual‑luciferase assay. In summary, LncRNA PVT1 inhibits the effect of miR‑16, promoting the cell cycle and inhibiting cellular apoptosis of cervical cancer cells, potentially via the NF‑κB pathway. The data from the present study will contribute to the current knowledge surrounding the theoretical basis of cervical cancer and provide a new perspective for the treatment of cervical cancer.

LncRNA-ENST00000501520 promotes the proliferation of malignant-transformed BEAS-2B cells induced with coal tar pitch mediated by target genes

As a human carcinogen, coal tar pitch (CTP) can significantly increase the risk of lung cancer. However, the mechanism underlying CTP-induced lung carcinogenesis has not been well understood. This study aims to explore the role of the LncRNA-ENST00000501520 in the proliferation of malignant-transformed human bronchial epithelial cells (BAES-2B) induced by CTP extract for the first time. BEAS-2B cells were stimulated with 2.4 μg/mL CTP extract, and then passaged for three times, which were named passage 1 and then passaged until passage 30 (named as CTP group). The ENST000001520 of cells in CTP group was interfered using siRNA. The results showed that ENST000001520 located in cell nucleus (>80%) had no or weak ability of protein encoding. After interference of ENST000001520, the migration and proliferation of cells in CTP group were inhibited, and the cell cycle was arrested in the G0/G1 phase; however, the apoptosis of cells in CTP group was promoted. The target genes (SKB1, CLTB, TAP2, PIPK2, and SOCS3) of ENST000001520 were screened out, and the mRNA and protein expression of SBK1 and SOCS3 was significantly decreased after ENST000001520 interference. SBK1 and SOCS3 may play a promoting role in occurrence and development of cancers. The study suggests that LncRNA-ENST00000501520 could promote the proliferation in malignant-transformed BEAS-2B cells induced with CTP extract which may be mediated by target genes. This study may provide a new target for prevention and treatment of lung cancer.

Long noncoding RNA actin filament-associated protein 1 antisense RNA 1 promotes malignant phenotype through binding with lysine-specific demethylase 1 and repressing HMG box-containing protein 1 in non-small-cell lung cancer

The number of documented long noncoding RNAs (lncRNAs) has dramatically increased, and their biological functions and underlying mechanisms in pathological processes, especially cancer, remain to be elucidated. Actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) is a 6810-nt lncRNA located on chromosome 4p16.1 that was first reported to be upregulated in esophageal adenocarcinoma tissues and cell lines. Here we reported that AFAP1-AS1, recruiting and binding to lysine-specific demethylase 1 (LSD1), was generally overexpressed in human non-small-cell lung cancer (NSCLC) tissues using quantitative real-time PCR. Higher AFAP1-AS1 expression was significantly correlated with larger tumor size (P = .008), lymph node metastasis (P = .025), higher TNM stage (P = .024), and worse overall survival in NSCLC patients. In vitro experiments revealed that AFAP1-AS1 downregulation inhibited cell migration and induced apoptosis; AFAP1-AS1 knockdown also hindered tumorigenesis in vivo. Moreover, mechanistic investigations including RNA immunoprecipitation and ChIP assays validated that AFAP1-AS1 repressed HMG box-containing protein 1 (HBP1) expression by recruiting LSD1 to the HBP1 promoter regions in PC-9 and H1975 cells. Furthermore, HBP1 functions as a tumor suppressor, and its ectopic expression hindered cell proliferation. Rescue assays determined that the oncogenic effect of AFAP1-AS1 is partially dependent on the epigenetic silencing of HBP1. In conclusion, our results indicate that AFAP1-AS1 is carcinogenic and that the AFAP1-AS1/LSD1/HBP1 axis could constitute a new therapeutic direction for NSCLC.

PVT1 Signaling Is a Mediator of Cancer Progression

There is increasing evidence that PVT1 has oncogenic properties and regulates proliferation and growth of many cancers. Themolecular mechanisms of action of PVT1 are mediated, in part, by microRNAs (miRNAs). However, some well-established transcription factors involved in cancer cell proliferation share a common thread of microRNA associations with PVT1. Furthermore, these microRNAs are also involved in mechanisms that lead to the development of drug resistance in cancer cells. While several microRNAs have been implicated directly in PVT1-mediated tumorigenesis, significant steps need to be taken to elucidate these important relationships. We synthesize the current knowledge of the miRNAs and associated genes by which PVT1 contributes to tumorigenesis. Overall, the trend suggests a negative correlation of microRNA expression with PVT1. It is clear that future studies involving PVT1 should be carried out in conjunction with microRNA analysis and should include large scale lncRNA-miRNA-mRNA network analysis. Likewise, the relationship between established transcription factors such as p53 and MYC, and processes like epithelial-mesenchymal transition may offer valuable insight into the yet unknown mechanisms of PVTI-mediated cancer progression via microRNA-dependent signaling networks.

Circular PVT1: an oncogenic non-coding RNA with emerging clinical importance

The importance of circular RNAs (circRNAs) in pathological processes like cancer is evident. Among the circRNAs, recent studies have brought circPVT1 under focus as the most potent oncogenic non-coding RNA. Recent studies on various aspects of circPVT1, including its biogenesis, molecular alteration and its probable role in oncogenesis, have been conducted for research and clinical interest. In this review, a first attempt has been made to summarise the available data on circPVT1 from PubMed and other relevant databases with special emphasis on its role in development, progression and prognosis of various malignant conditions. CircPVT1 is derived from the same genetic locus encoding for long non-coding RNA lncPVT1; however, existing literature suggested circPVT1 and lncPVT1 are transcripted independently by different promoters. The interaction between circRNA and microRNA has been highlighted in majority of the few malignancies in which circPVT1 was studied. Besides its importance in diagnostic and prognostic procedures, circPVT1 seemed to have huge therapeutic potential as evident from differential drug response of cancer cell line as well as primary tumors depending on expression level of the candidate. circPVT1 in cancer therapeutics might be promising as a biomarker to make the existing treatment protocol more effective and also as potential target for designing novel therapeutic intervention.

A long non-coding RNA LINC01288 facilitates non-small cell lung cancer progression through stabilizing IL-6 mRNA

The non-small cell lung cancer (NSCLC) denotes a malignant type of cancers. Long non-coding RNAs (lncRNAs) can actively participate in cancer development. However, the exact role of lncRNAs in NSCLC remains largely elusive. In current work, we report a novel intergenic lncRNA LINC01288 involved in NSCLC. We found that LINC01288 is frequently upregulated in NSCLC samples and cell lines. LINC01288 significantly promotes viability, migration, xenograft tumor growth and metastasis in vitro and in vivo. LINC01288 physically interacts with the IL-6 mRNA and increase the stability of IL-6 transcripts. Subsequently, the autocrine induction of IL-6 and enhanced STAT3 activation may facilitate NSCLC progression. Collectively, our data have demonstrated that LINC01288 serves as a crucial mediator of IL-6/STAT3 pathway and created novel interplay between lncRNAs and tumor development.

Knockdown of lncRNA PVT1 Inhibits Vascular Smooth Muscle Cell Apoptosis and Extracellular Matrix Disruption in a Murine Abdominal Aortic Aneurysm Model

This study was designed to determine the effects of the long non-coding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) on vascular smooth muscle cell (VSMC) apoptosis and extracellular matrix (ECM) disruption in a murine abdominal aortic aneurysm (AAA) model. After injection of PVT1-silencing lentiviruses, AAA was induced in Apolipoprotein E-deficient (ApoE-/-) male mice by angiotensin II (Ang II) infusion for four weeks. After Ang II infusion, mouse serum levels of pro-inflammatory cytokines were analysed, and aortic tissues were isolated for histological, RNA, and protein analysis. Our results also showed that PVT1 expression was significantly upregulated in abdominal aortic tissues from AAA patients compared with that in controls. Additionally, Ang II treatment significantly increased PVT1 expression, both in cultured mouse VSMCs and in AAA murine abdominal aortic tissues. Of note, the effects of Ang II in facilitating cell apoptosis, increasing matrix metalloproteinase (MMP)-2 and MMP-9, reducing tissue inhibitor of MMP (TIMP)-1, and promoting switching from the contractile to synthetic phenotype in cultured VSMCs were enhanced by overexpression of PVT1 but attenuated by knockdown of PVT1. Furthermore, knockdown of PVT1 reversed Ang II-induced AAA-associated alterations in mice, as evidenced by attenuation of aortic diameter dilation, marked adventitial thickening, loss of elastin in the aorta, enhanced aortic cell apoptosis, elevated MMP-2 and MMP-9, reduced TIMP-1, and increased pro-inflammatory cytokines. In conclusion, our findings demonstrate that knockdown of lncRNA PVT1 suppresses VSMC apoptosis, ECM disruption, and serum pro-inflammatory cytokines in a murine Ang II-induced AAA model.

microRNA-497 inhibition mitigates myocardial infarction via enhancing wingless/integrated signal pathway in bone marrow mesenchymal stem cells

OBJECTIVE

High association between microRNA-497 (miR-497) inhibition and the improvement of myocardial infarction (MI) has been proved. Bone marrow mesenchymal stem cells (BMSCs) therapy is regarded as a highly promising approach to MI treatment. We studied the functional role of miR-497 inhibition in the transplantation of BMSCs for MI treatment.

METHODS

BMSCs were isolated from 10 to 14 days old male Sprague-Dawley (SD) rats for in vitro and in vivo experiments. First, flow cytometry was used for BMSCs identification. miR-497 antagomir and agomir were transfected into BMSCs, and the migratory capacity was detected by wound healing assay. Protein levels were analyzed by Western blot analysis. Second, rat MI models were constructed and injected with each experimental group BMSCs. Four weeks later, the cellular morphology of cardiomyocyte and infarcted size was observed after histopathologic evaluation (HE) and Masson's trichrome staining. Moreover, WNT3A siRNA (siWNT3A) was used for further investigating the involvement of Wnt/β-catenin pathway.

RESULTS

BMSCs were confirmed to be CD90+ CD45- CD11b/c- cells. The number of rats with wound closure increased more in miR-497 inhibitor group than that in agomir group, the number markedly decreased in agomir group ( P < 0.01). As the miR-497 decreased, the protein levels of WNT3A, matrix metalloproteinase-9 and β-catenin were notably increased. The injection of BMSCs inhibiting miR-497 repaired almost all infarcted zones. siWNT3A, on the contrary, could decrease the wound closure rate and relative protein levels and inhibit MI treatment.

CONCLUSION

miR-497 antagomir contributes to BMSCs transplantation for MI treatment by Wnt/β-catenin activation, and Wnt/β-catenin pathway is essential for the functional effects of miR-497 antagomir.

Knockdown of lncRNA PVT1 Inhibits Glioma Progression by Regulating miR-424 Expression

Plasmacytoma variability translocation 1 (PVT1), an oncogene, has been reported to be highly expressed in many tumors, including human glioma, gastric cancer, and non-small cell lung cancer. Functionally, it could also regulate the development of tumor cells. However, its specific roles and pathogenesis in human gliomas are still not clear. This study investigated the function and mechanism of PVT1 knockdown in the proliferation and malignant transformation of human gliomas. We first examined the expression levels of PVT1 and miR-424 in human glioma tissues and cell lines. We also used gene manipulation techniques to explore the effects of PVT1 knockdown on cell viability, migration, invasion, and miR-424. We found that PVT1 knockdown effectively inhibited cell viability, migration, and invasion of human glioma cells and increased miR-424 expression. Based on the negative correlation between PVT1 and miR-424, we then confirmed the direct interaction between PVT1 and miR-424 using RNA immunoprecipitation (RIP) and luciferase reporter assays. Further, we established a xenograft nude mouse model to determine the role and mechanism of PVT1 on tumor growth in vivo. In addition, PVT1 knockdown was shown to promote miR-424 in vivo. In summary, the present study demonstrated that PVT1 knockdown could negatively regulate miR-424 to inhibit human glioma cell activity, migration, and invasiveness. PVT1 knockdown could negatively regulate miR-424 to inhibit cellular activity, migration, and invasiveness in human gliomas, which explained the oncogenic mechanism of PVT1 in human gliomas. It also suggested that PVT1 might be a novel therapeutic target for human gliomas.

Autophagy-Modulating Long Non-coding RNAs (LncRNAs) and Their Molecular Events in Cancer

Cancer is a global threat of health. Cancer incidence and death is also increasing continuously because of poor understanding of diseases. Although, traditional treatments (surgery, radiotherapy, and chemotherapy) are effective against primary tumors, death rate is increasing because of metastasis development where traditional treatments have failed. Autophagy is a conserved regulatory process of eliminating proteins and damaged organelles. Numerous research revealed that autophagy has dual sword mechanisms including cancer progressions and suppressions. In most of the cases, it maintains homeostasis of cancer microenvironment by providing nutritional supplement under starvation and hypoxic conditions. Over the past few decades, stunning research evidence disclosed significant roles of long non-coding RNAs (lncRNAs) in the regulation of autophagy. LncRNAs are RNA containing more than 200 nucleotides, which have no protein-coding ability but they are found to be expressed in most of the cancers. It is also proved that, autophagy-modulating lncRNAs have significant impacts on pro-survival or pro-death roles in cancers. In this review, we highlighted the recently identified autophagy-modulating lncRNAs, their signaling transduction in cancer and mechanism in cancer. This review will explore newly emerging knowledge of cancer genetics and it may provide novel targets for cancer therapy.

Roles of Oncogenic Long Non-coding RNAs in Cancer Development

Long non-coding RNAs (lncRNAs) are classified as RNAs that are longer than 200 nucleotides and cannot be translated into protein. Several studies have demonstrated that lncRNAs are directly or indirectly involved in a variety of biological processes and in the regulation of gene expression. In addition, lncRNAs have important roles in many diseases including cancer. It has been shown that abnormal expression of lncRNAs is observed in several human solid tumors. Several studies have shown that many lncRNAs can function as oncogenes in cancer development through the induction of cell cycle progression, cell proliferation and invasion, anti-apoptosis, and metastasis. Oncogenic lncRNAs have the potential to become promising biomarkers and might be potent prognostic targets in cancer therapy. However, the biological and molecular mechanisms of lncRNA involvement in tumorigenesis have not yet been fully elucidated. This review summarizes studies on the regulatory and functional roles of oncogenic lncRNAs in the development and progression of various types of cancer.

Prognostic values of long noncoding RNA PVT1 in various carcinomas: An updated systematic review and meta-analysis

Cancers have been a worldwide health problem with a high mortality rate, but ideal biomarkers are not available to effectively screen and diagnose patients. Currently, an increasing number of long noncoding RNAs have been reported to be abnormally expressed in human carcinomas and play a vital role in tumourigenesis. Plasmacytoma variant translocation 1 (PVT1) is upregulated in various carcinomas, and its overexpression is associated with poor survival in cancer patients. We conduct an updated meta-analysis to determine its potential in prognosis for tumours. In total, 14 studies comprising 2435 patients were enrolled according to Reporting Recommendations for Tumour Marker Prognostic Studies guidelines. High PVT1 expression indicated poor overall survival (hazard ratio [HR] = 1.98, 95% confidence interval [CI]: 1.62-2.42, P < 0.00001) and disease-free survival (HR = 1.63, 95% CI: 1.45-1.84, P < 0.00001). Additionally, increased PVT1 expression was positively associated with lymphatic node metastasis (odd ratio [OR] = 2.87, 95% CI: 1.66-4.96, P = 0.0002), distant metastasis (OR = 2.47, 95% CI: 1.74-3.50, P < 0.00001), advanced tumour-node-metastasis stages (OR = 2.59, 95% CI: 1.38-4.88, P = 0.003). New findings highlight that PVT1 acts as competing RNA to microRNAs to protect mRNAs from miRNAs repression. Therefore, we also discuss PVT1-related microRNAs and their interaction in tumourigenesis. In conclusion, PVT1 may be a potential biomarker of poor prognosis for patients with different cancer types.

LncRNA PVT1 Facilitates Tumorigenesis and Progression of Glioma via Regulation of MiR-128-3p/GREM1 Axis and BMP Signaling Pathway

The current research was aimed at probing into the role of long noncoding RNA (lncRNA) PVT1 in the pathogenesis of glioma and the regulatory mechanism of PVT1/miR-128-3p/GREM1 network in glioma via regulation of the bone morphogenetic protein (BMP) signaling pathway. Microarray analysis was used for preliminary screening for candidate lncRNAs and mRNAs in glioma tissues. Real-time quantitative polymerase chain reaction, Western blot, MTT assay, flow cytometry, migration and invasion assays, and xenograft tumor model were utilized to examine the influence of the lncRNA PVT1/miR-128-3p/GREM1 network on the biological functions of glioma cells. Luciferase assay and RNA-binding protein immunoprecipitation assay were used to validate the miR-128-3p-target relationships with lncRNA PVT1 or GREM1. In addition, the impact of GREM1 on BMP signaling pathway downstream proteins BMP2 and BMP4 was detected via Western blot. LncRNA PVT1 was highly expressed in human glioma tissues and significantly associated with WHO grade (I-II vs III-IV; p < 0.05). There existed a regulatory relationship between lncRNA PVT1 and miR-128-3p as well as that between miR-128-3p and GREM1. MiR-128-3p was downregulated, whereas GREM1 was upregulated in glioma tissues in comparison with para-carcinoma tissues. Overexpression of GREM1 promoted the proliferation and metastatic potential of glioma cells, whereas miR-128-3p mimics inhibited the glioma cell activity through targeting GREM1. Furthermore, lncRNA PVT1 acted as a sponge of miR-128-3p and, thus, influenced the BMP signaling pathway downstream proteins BMP2 and BMP4 through regulating GREM1. LncRNA PVT1 modulated GREM1 and BMP downstream signaling proteins through sponging miR-128-3p, thereby promoting tumorigenesis and progression of glioma.

Long non-coding RNA SNHG15 promotes CDK14 expression via miR-486 to accelerate non-small cell lung cancer cells progression and metastasis

Long non-coding RNAs (lncRNAs) have been validated to play important role in multiple cancers, including non-small cell lung cancer (NSCLC). In present study, our team investigate the biologic role of SNHG15 in the NSCLC tumorigenesis. LncRNA SNHG15 was significantly upregulated in NSCLC tissue samples and cells, and its overexpression was associated with poor prognosis of NSCLC patients. In vitro, loss-of-functional cellular experiments showed that SNHG15 silencing significantly inhibited the proliferation, promoted the apoptosis, and induced the cycle arrest at G0//G1 phase. In vivo, xenograft assay showed that SNHG15 silencing suppressed tumor growth of NSCLC cells. Besides, SNHG15 silencing decreased CDK14 protein expression both in vivo and vitro. Bioinformatics tools and luciferase reporter assay confirmed that miR-486 both targeted the 3'-UTR of SNHG15 and CDK14 and was negatively correlated with their expression levels. In summary, our study conclude that the ectopic overexpression of SNHG15 contribute to the NSCLC tumorigenesis by regulating CDK14 protein via sponging miR-486, providing a novel insight for NSCLC pathogenesis and potential therapeutic strategy for NSCLC patients.

Long non-coding RNA PVT1 promotes malignancy in human endometrial carcinoma cells through negative regulation of miR-195-5p

The plasmacytoma variant translocation 1 (PVT1)1 gene is a long non-coding RNA (lncRNA)2 that has been shown to be an oncogene in many cancers. Herein, the function and potential molecular mechanisms connecting PVT1 and miR-195-5p were elucidated in endometrial cancer cell lines. Quantitative real-time PCR and fluorescence in situ hybridization (FISH)3 demonstrated that PVT1 is up-regulated concomitant with miR-195-5p down-regulation in human endometrial carcinoma tissues. PVT1 knockdown inhibited cell proliferation, migration, and invasion while facilitating apoptosis of endometrial cancer cells. Moreover, restoration of miR-195-5p due to PVT1 knockdown exerted tumor-suppressive functions. We observed that PVT1 promotes malignant cell behavior by decreasing miR-195-5p expression. Binding of PVT1 and miR-195-5p was confirmed using luciferase assays. Furthermore, expression of miR-195-5p negatively correlates with PVT1 expression. At the molecular level, either PVT1 knockdown or miR-195-5p overexpression resulted in a decrease of acidic fibroblast growth factor receptor (FGFR1)4 and basic fibroblast growth factor (FGF2).5 FGFR1 and FGF2 are targets of miR-195-5p that play a critical role in endometrial carcinoma by activating PI3K/AKT and MAPK/Erk pathways. Remarkably, PVT1 knockdown combined with miR-195-5p overexpression led to tumor regression in vivo. Overall, these results depict a novel pathway mediated by PVT1 in endometrial carcinoma, which may have potential application for endometrial carcinoma therapy.

Long non-coding RNA PVT1 promotes cell proliferation and invasion through regulating miR-133a in ovarian cancer

The long non-coding RNA, plasmacytoma variant translocation 1 (PVT1), was reportedly to be highly expressed in a variety of tumors including ovarian cancer (OC). However, the role and mechanism of action of PVT1 in the carcinogenesis and progression of OC remains largely unknown. PVT1 and miR-133a expression were detected by quantitative real time PCR(qRT-PCR) assays in OC tissues and cell lines. Cell Counting Kit-8 (CCK-8), flow cytometer, wound healing and transwell invasion assays were performed to evaluate cell proliferation, cycle, migration and invasion abilities, respectively. qRT-PCR and luciferase reporter assays demonstrated PVT1 regulated miR-133a expression. Here, we discovered that PVT1 shows higher expression in OC tissues than in normal ovarian tissues, and patients who show higher expression of PVT1 have worse progression-free and overall survivals compared to lower expression of PVT1. Additionally, we observed that knockdown of PVT1 significantly inhibited OC cell proliferation, and decreased the migration and invasion capabilities of OC cells. Mechanistically, miR-133a was identified to serve as a direct downstream target of PVT1 in OC. Knockdown of PVT1 inhibited cell proliferation, migration and invasion through negative regulating miR-133a in OC cells. Taken together, our finding shows that PVT1 may be a novel biomarker for prognosis and a promising therapeutic target for OC.